Accelerometry data from the National Health and Nutrition Examination Study confirms what has been suspected from self-report: after adolescence, people in the United States are very inactive. With age, even this modest activity declines further. Accelerometry data was collected on a subsample of participants from the Health, Aging, and Body Composition study in the year 10 and year 16 clinical examinations. We are working with this data to study the paterns of true daily activity in older adults. Additionally, we have collected accelerometry and sleep data in a subsample of participants from the Age, Gene/Environment Susceptibility Study in Iceland. Also, as part of this project, we will compare measurements from accelerometers worn at various locations on the body while eldery participants conduct activities of daily living. And, finally, we are testing the use of accelerometers to assess recovery of function after surgery in the elderly.